Formation of NaF‐Rich Solid Electrolyte Interphase on Na Anode through Additive‐Induced Anion‐Enriched Structure of Na⁺Solvation

Abstract

High-capacity sodium (Na) anodes suffer from dendrite growth due to the high reactivity, which can be overcome through inducing a stable NaF-rich solid electrolyte interphase (SEI). Herein, we propose an additive strategy for realizing the anion-enriched structure of Na + solvation to obtain a NaF-rich SEI. The electron-withdrawing acetyl group in 4-acetylpyridine (4-APD) increases the coordination number of PF 6 À in the Na + solvation sheath to facilitate PF 6 À to decompose into NaF. Thus, the NaF-rich SEI with high mechanical stability and interfacial energy is formed to repress the growth of Na dendrites. With the 4-APD-contained electrolyte, the symmetric Na j j Na cells show excellent cycling performance over 360 h at 1.0 mA cm À 2 . Meanwhile, excellent stability is also achieved for Na j j Na 3 V 2 -(PO 4 ) 2 O 2 F full cells with high Coulombic efficiency (97 %) and capacity retention (91 %) after 200 cycles.

Gradient Designs for Efficient Sodium Batteries

“…Yet, their low modulus cannot inhibit the growth of sodium dendrites during long cycles. On the other side, inorganic sodium species such as NaF, Na 2 O, and Na 3 N have high interfacial energy and weak bonding with electrode materials, which facilitate the transport kinetics of Na ions to restrain dendrite generation. , However, inorganic SEI films are fragile and prone to fracture during the volume change of sodium metal. Therefore, an ideal SEI should be a rational combination of organic and inorganic species to maintain its stability and robustness, while the relative ratios vary case in case.…”

Magnetoelectric synergy strategy for superior iron disulfide anode

“…Remarkably, building a mechanically interlocked structure is desirable to improve structure stability during repeated (de) sodiation processes. [21][22][23] Building a heterojunction has been shown to reduce the activation barrier, including expediting kinetic behavior and promoting dendrite-free energy storage systems, [24][25][26] which are key features in SIBs. In this respect, the difference in energy levels between FeS 2 and VS 2 , i.e.…”

Highly [001]-oriented N-doped orthorhombic Nb2O5 microflowers with intercalation pseudocapacitance for lithium-ion storage

“…With the rapid expansion of electric drive vehicles (EDVs) and energy storage systems (ESSs), strong demand for safe lithiumion batteries (LIBs) with high power and energy density becomes inevitable. [1][2][3] Most recently, rather than the diffusion-controlled Li + storage mechanism, the distinct pseudocapacitive mechanisms have been confirmed to be favorable for realizing ultra-fast discharge without deteriorating the special capacity. [4][5][6] The pseudocapacitor-type Li + storage mechanisms are based on charge-transfer faradaic reaction at the electrode surface (redox pseudocapacitance) or on fast Li + insertion between layers or in tunnels of the electrodes (intercalation pseudocapacitance).…”